Nicotinamide riboside (NR) is a naturally occurring antioxidant that is converted to NAD+ in the body. NMN is also used to generate NAD+, which provides power and energy to cells. NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell of the body. NR and NMN are two of the most prominent NAD+ precursors on the market today.